1. Field
The invention is in the field of fire-retardant compositions of matter, particularly those useful for treating cellulosic materials such as cotton batting and ground waste paper insulation.
2. State of the Art
Boric acid in powder form has long been used as a fire retardant for cellulosic materials of the type with which this invention is particularly concerned. My prior invention disclosed by U.S. Pat. No. 3,983,040 as issued Sept. 28, 1976, under the title "Fire-Retardant Composition and Process of Producing Same", provided an effective and relatively economical substitute for the boric acid previously employed, although only about 80% as effective by weight. The fire-retardant composition of that invention comprises a particulate reaction product of a borate ore and sulfuric acid, the ore having been selected from the group consisting of calcium, sodium, magnesium, and potassium borates, and mixtures thereof. The reaction product contains boric acid and a significant quantity of one or more sulfates selected from the group consisting of calcium, sodium, magnesium, and potassium sulfates. The ore is preferably finely ground prior to the application thereto of the acid, and water is added during mixing of the ore and acid. Heat produced exothermically during the mixing aids in drying the reaction product, whereupon it is pulverized to a fine powder ready for use.